feature: add Avo

[adrianthedev]

What's this PR do?

This PR adds the first iteration of Avo. I'd like to spend a bit more time to figure out how the database is modeled.

It also adds a navbar in the layout as a kickstart for thinking about design.

Still to do

I haven't figured out how to add the /avo path behind a check that the user is an admin. Will look into it.

Where should the reviewer start?

No place in particular.

How should this be manually tested?

Run the code and try out /avo

Screenshots or Video

[adrianthedev]

~I'm having a bit of trouble querying different types of users (mentors or applicants). Maybe @andycroll, or someone that thought about this architecture can help me understand.~

~In particular, I'm trying to get all the users that are mentors or all the users that are applicants. What kind of active record query should one make? I tried something along the lines of User.joins(:mentorship_roles_as_mentor) but that returned an empty array.~

[adrianthedev]

I ditched the Applicant and Mentor Avo resources and tweaked the fields a bit. So this is the initial iteration on adding Avo.

Things that we can do:

• add search
• add searchable belongs_to so the mentorship dropdowns won't crash if there are many users
• add actions to mark users as unsubscribed, verified, etc.
• add filters

I would love to get access to the production DB, or something similar. With real data we can spot many things to improve.

[andycroll]

There's no production yet!

[andycroll]

Got some test failures.

[adrianthedev]

On it this week.